[ha] Introduction & CAN

Vermeulen Nic (Nic.Vermeulen.at.mapp.rma.ac.be)
Wed, 2 Dec 1998 15:47:35 +0100

Hello all and welcome to this list

Never thought that a simple post would induce soo many new members. I
even see an old acquaintance has found us, welcome back Andrew. Maybe
some of you would like to know how this all started and where we are
heading to? A bit of history. This list is a result of a post approx. 3
months ago to run into some like-minded people. After we discussed some
major points and desires, Robin set himself up as a
moderator/administrator (and he does that very well). From those first
discussions, we gathered some general targets which are published on the
site. Keep in mind that everything you say here falls under the GNU
public license. If you reveal some highly secret projects of your
employer, don't blame us if we use them in a design.
Speaking of design: As you may have read, we are trying to build
something that can be copied by every keen hobbyist. I see myself as a
keen hobbyist and I build a lot of things myself (including measurement
appliances), but I hate designs that apply specialized equipment in
order to rebuild. I always give the example of an EPROM burner (here we
go again). If you choose your MCU's carefully, you can avoid the need of
a burner using the isp capability and a bit of software. For more info
on our goals and restrictions, see the website.

What about me! As you may have noticed, english is not my native
language and I can imagine that you guys frown your eyebrows sometimes.
Sorry for that. I'll do the best possible. I'm an electronics engineer
from Belgium involved in the design & testing of hardware for laser
based systems and data acquisition. Well, since a couple of years, I'm
more into system planning. They call it promotion? That's why I'm on the
list. I miss being VP of engi... no, cut that, I miss the smell of my
solder iron, the testing probes, scopes etc... My software experience is
rather limited to a bit of windows programming (C++/pascal on Win3.11)
and some small test routines on several MCU's I worked with
(68xx,68K,'51 and ..,ST62 and since pics are popular, I'm trying to gain
insight in pics).

This is something for Lars: You said you used RS485 for can. But if 2
can drivers (75176) send different things (0 and 1), high currents will
flow between the 2 devices and they 'll turn into a protective thermal
shutdown mode. How do you deal with that? Second, do you have a protocol
spec. In other words, would it be possible to implement (a portion of)
CAN in another µC. I ask this because you mentioned 505C and 515C with
on board CAN. The IC's have a 68PLCC package wich I believe takes up too
much boardspace is you want to hide things behind a wallplate (at least
in my case). CAN in a 8pin pic would be ideal. Maybe I'm rushing things
but I was just wondering.
And then the typical Swedish problem with the 3 phases ;o) Don't worry,
same here. We should be able to solve this by 'bridging' them (e.g. put
a repeater between the 3 lines). How does professional equipment cope
with that?
And how does CAN handle speed if you have a slow and a fast device on
your line? Is there some negotiation algorithm?

One last thing. Since we are so many know, I can imagine that we discuss
different topics at the same time. I would suggest that you write the
topic between square brackets before the subject. So the header could
look like "Re:[ha][HARDWARE] some hardware problem".

Ok, enough of that. Hope we all learn from eachother and that you may
find your kicks here.

CU

Zeb

PS: Wonder why I always write Zeb. Back in 1982 I wrote an arcade game
called Zebedeus. Ever since, friends are calling me Zeb.